191999-28-7Relevant articles and documents
Ag2O nanoparticle-catalyzed substrate-controlled regioselectivities: direct access to 3-ylidenephthalides and isocoumarins
Chaudhary, Sandeep,Shyamlal, Bharti Rajesh K.,Yadav, Lalit,Tiwari, Mohit K.,Kumar, Krishan
, p. 23152 - 23162 (2018/07/10)
Herein, we disclose the first example of an efficient, silver oxide nanoparticle-catalyzed, direct regioselective synthesis of 3-ylidenephthalides 11-16 and isocoumarins 17-20via sonogashira type coupling followed by substrate-controlled 5-exo-dig or 6-endo-dig cyclization reaction, respectively. This one pot coupling involves reaction of substituted 2-halobenzoic acid with meta/para-substituted and ortho-substituted terminal alkynes, which proceeded in a regioselective manner resulting in the formation of 3-ylidenephthalides or isocoumarins, respectively, in excellent yields (up to 95%) with complete Z-selectivity. This protocol features relatively broad substrate scope, mild conditions, operational simplicity, and is favourable with aromatic/alicyclic terminal alkynes. The competition experiments and gram-scale synthesis further highlight the importance and versatility of the methodology. The proposed mechanistic pathways illustrate that the regioselectivity is substantially being controlled by the substituent(s) present on the acetylenic phenyl ring.
PHTHALAZINONE DERIVATIVES
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Page/Page column 65-66, (2008/12/07)
A compound of the formula (I) wherein: A and B together represent an optionally substituted, fused aromatic ring or an optionally substituted, fused cyclohexene ring; D is selected from: (i), where Y1 is selected from CH and N, Y2 is selected from CH and N, Y3 is selected from CH, CF and N and Y4 is selected from CH and N; (ii) where Y1is selected from CH and N and Y2 is selected from CH and N; (iii) and where Q is O or S; and (iv), where Q is O or S; and RD is an optionally substituted C5-20 aryl group, bound to D by a carbon-carbon bond.
Sigmatropic Rearrangements of 1,1-Diarylindenes. Migratory Aptitudes of Aryl Migration in the Ground and Electronically Excited States
Manning, Carl,McClory, Michael R.,McCullough, John J.
, p. 919 - 930 (2007/10/02)
The photochemical and thermal rearrangements of 1,1-diarylindenes to give 2,3-diarylindenes have been investigated.Migratory aptitudes of p-X-phenyl vs. phenyl were determined for X =Br,CN, and OCH3 in the photochemical and thermal migrations.The identities of the products of these rearrangements were established by unambiguous synthesis, and the synthetic work is described.Product ratios were generally determined by NMR techniques, but VPC and isotope dilution were also used in the case of 1-(p-cyanophenyl)-1-phenylindene reactions.The excited-state reactions (direct and triplet sensitized) are highly selective, migration of the substituted phenyl group being favored for all three substituents.The thermal reactions, in contrast, are quite unselective, phenyl migrating almost as readily as the substituted phenyl group in all cases.Quantum yields for the rearrangement in the case of 1,1-diphenylindene and 1-(p-cyanophenyl)-1-phenylindene were 0.80 and 0.4, respectively (direct irradiation), and 0.43 and 0.53 (sensitized reactions).The results of the thermal reactions and results from the literature are discussed in terms of bond-dissociation energies and transition-state-delocalization energies calculated by using the Hueckel theory.Neither approach led to a satisfactory interpretation.The excited-state migrations are consistent with charge-transfer stabilization of the transition state, which can be estimated from oxidation and reduction potentials by using Weller's equation.
